Why would Yoda and Obiwan go into hiding at the end of episode 3. They believed Anikin to be dead. Did they think they wouldn't get another shot at at Sidious? Just biding their time for the Empire to weaken to make a move? Maybe they hoped other Jedi would survive and they could regroup. You would at least think Obiwan or Yoda would finish Vader when they learned he survived. What would make them think the Twins would be able to get a shot at Sidious?
"Palpatine faced (and killed) Mace and Agen and Kit and Saesee - four of the greatest swordsmen our Order has ever produced. By himself. Even both of us together wouldn't have a chance." - Obi-Wan Kenobi, Episode III novelization And after Yoda's aborted attempt, there was zero chance of getting anywhere near him again. They literally had the whole Imperial war machine standing squarely in their way. If Obi-Wan hadn't faced and damaged Vader at that point, before his Sith training could truly begin, he would have been invincible. Even Palpatine couldn't have lasted long against a fully trained, self-controlled and power-filled Vader. As it was he was left literally half the man he could have been, making it just barely possible that his own flesh and blood, with access to his level of power, could destroy him.
The Jedi were obliterated. They probably figure Luke and Leia would give them a base to rebuild the order.
Yeah, hundreds of massive space cruisers, millions of clones, thousands of lightyears worth of space to get near him, only to face the most powerful forceuser in history with only a muppet and a washed up Glaswegian is not going to end well.
Granted they couldn't get near Sidious. But they could take out Vader. And they waited 20years to do anything. In that time, the last vestiges of the Confederacy were wiped out. They could have shown those people both sides had been played by Sidious and continued the fight on the other side. Instead it completely winds down and the Empire clamps down on the galaxy and grows stronger. And they choose to wait on only Luke and Leia to rebuild the order? They were in the Temple after Order 66. Did the novelization of Sith say Sidious captured the holicrons containing all the known force sensitives the Jedi had on record? if not they could have started rebuilding sooner. Doesn't sound like Yoda was doing much. Sorry it's a good story, but when you think about these things you wonder what they were thinking. It's almost as if Yoda knew all along the twins were the key.
The novelization does indeed say that the holocrons and archives were seized, so an all-out pogrom on Force sensitives would have taken place very quickly. Of course Yoda knew. Qui-Gon told him as much. Even if he hadn't, the mere fact that they were children of the (potentially, until Mustafar) strongest Force-sensitive in history would have made them a formidable weapon indeed. And they would need someone alive to teach them, so Yoda and Obi-Wan could only stick their necks out so far until then. Obi-Wan only survived Vader the first time because the young Sith let his anger and ego get the better of him. In essence, Vader defeated himself. He'd never make that mistake again (against one or both Jedi), and didn't on the Death Star.
Could they? Vader is the Emperor's right hand man, arguably the second-most powerful person in the entire Empire, not to mention the entire Imperial military was his to personally command. Even if the successfully snuck onto Vader's Star Destroyer and into the room he keeps his life support pod, what good would it do? Even assuming they managed to get the upper hand in a lightsabre fight, Vader could trigger an alarm, and I doubt the two of them would last long against a few hundred stormtroopers not to mention the ship's crew. Maybe he did?
Because Obi and Yoda were in hiding at the start of episodes IV and V. In all seriousness though, Yoda and Obi-Wan were pretty foreword thinking and proactive characters in the PT. There would be a rebellion that would quell up to oppose the Empire and Emperor, but the remaining Jedi had no part in it for more than 20 years.
Taking out Vader or even Sidious on their own wouldn't change much in the long run. They needed to take them both out or the survivour would just recruit a new apprentice and the Sith would just keep on ruling the galaxy. The reason they went into hiding is because they had their shot at the Emperor and they blew it. Yoda would never be able to get that close again. The only way to do it is by training a Jedi that Palpatine will want brought before him and Vader. That means either Luke or Leia, who were currently less than a day old, so going into hiding until they're ready is the only option.
When you've got the Emperor's favor, as Tarkin (and in an deleted scene from ROTJ, Jerjerrod) did, you can afford to stand up to Vader. 'Darth' is hardly a military rank, and Vader knows better than to openly defy the Emperor's wishes by killing one of his pets. The Executor was Vader's personal ship, the Hoth task force placed in his care by the Emperor, so Vader could do whatever the hell he liked with the crew.
From Chelfelf's 91 Reasons to Hate Star Wars: Episode III: Revenge of the Sith: Reason #66: "For the clones to discover the recalibration, a long time it will take." There is a coded message being sent out for all Jedi to return to the Jedi temple. Yoda and Obi-Wan agree that they have to recalibrate the code so that more Jedi do not fall into the trap. This is very handy, because warning the Jedi to stay away leaves the possibility for a much greater number of expanded universe novels, TV shows and video games to feature Jedi survivors doing Jedi things like flipping around, using lightsabers and flipping around some more. After Obi-Wan recalibrates the code, Yoda then says, "For the clones to discover the recalibration, a long time it will take." If Yoda says it, it must be true! Had Yoda not said anything, the scene would have just been simply unmemorable. Choosing to open his big mouth and explain it poorly raises the question: "Why?" Reason #67: Yoda & Obi-Wan's Plan Yoda decides that he and Obi-Wan must split up, because any good plan usually begins with splitting up. Yoda will take care of Palpatine, and Obi-Wan will kill Anakin. Obi-Wan disagrees with this plan, because he doesn't think he can kill Anakin, being that they are so close. It is unclear why, seeing that Anakin is so far away, they don't both attack Palpatine together, then go for Anakin together as well. It's especially puzzling since every single battle the Jedi have had with the Sith have been two-on-one affairs: Qui-Gon and Obi-Wan versus Darth Maul, Obi-Wan and Anakin versus Count Dooku, Obi-Wan and Anakin versus Count Dooku again. I worry about the collective wisdom of Obi-Wan and Yoda if they choose now to finally level the playing field and have a fair one-on-one fight. ... yeah.
Remember the battle with Dooku in the opening act of ROTS? Dooku owned Obi-Wan with the Force and took him out of the fight. Now consider that Palpatine is stronger in the Force than Dooku. Do the math. This was spelled out to an extent in the novelization.
Also, there is a certain kind of logic in that attacking Palpatine and Anakin simultaneously is the best way to catch both off guard. If Obi-Wan and Yoda worked together and fought Palpatine, even if they defeated, Anakin would be expecting them and would thus have time to prepare, which as we all know is how Batman wins the day. It's flimsy, but it kind of works.
I hope that the new canon (Rebels, novels, comics) shows both Yoda and Obi-Wan actually being more active during The Dark Times than we know thus far. I will say that I agree with those who feel that Obi-Wan and Yoda should've teamed up to take down Palpatine. That made more sense to me than them splitting up. If they had been able to take down Palpatine they could've moved on Anakin who might have still been on Mustafar with Padme or heading back to Coruscant without knowing that Palpatine was dead. We don't know if he was as attuned as Palpatine was to him.
Yeah, I felt that Obi-Wan's skills were unevenly portrayed, like other Jedi, especially when it came to Obi-Wan and Dooku. I mean Obi-Wan took out Darth Maul, General Grevious, and Darth Vader, but he got taken out way too easily by Dooku. It felt more storyline dictated. I don't want to take anything anyway from Dooku, who I do like, but Obi-Wan should've been portrayed more competently when facing him, especially in ROTS. Palpatine is my favorite Star Wars character but I got to say he took out so many Jedi Masters because they didn't expect it. They didn't know how it was going to go until Palpatine revealed himself. Mace, then more on guard, presented more of a challenge. Yoda and Obi-Wan would've gone into the battle with Palpatine with their eyes open.
Unless you subscribe to the belief Palpatine allowed Mace to get the upper hand to test Anakin and could have defeated Mace at any time during the fight had he wished to, which is still heavily debated in fandom to this day.
There are a few points that could be suggested to explain some of these supposed discrepancies. In Anakin's case it's been said that Anakin acted rashly and impatiently, due to emotion, and that Obi-Wan would/could have lost were that not the case. Anakin had only recently turned to the dark side and lacked control. This gets into the issue of experience vs. midichlorian count. Arguably both factors are likely to be important in one's actualized Force ability ( we may note the Force push stalemate ). In the case of Grievous ( not Grevious ), he isn't even a Force user! We might find ourselves wondering why Jedi even have as much trouble with him as they sometimes do. When characters like Obi-Wan or Kit use a potent Force push on him, it's gratifying because it only makes sense. Obi-Wan vs. Maul ( the first time, heh ) is what it is. It played well in 1999, but in retrospect, if we're being critical, it looks like Maul should have had time to realize what was going on and defend himself. Spoiler Going by Rebels, at least, it seems that Yoda was a little more active in the Dark Times than we originally knew.
The best answer I can think of is "because that's how it was in the original trilogy". Though there was never stated that either were actually in hiding from the Empire. I always assumed that the two planets were their homes when they weren't working as Jedi. We were never given an indication that they were being hunted, so it seems kind of silly that they were hiding from anything.